Purpose: We recently reported that the degeneration and destruction of femoral articular cartilage and osteophytes showed a greater degree of deterioration than those of the tibial and patellar articular side in early-stage of knee OA using 3TMRI and T2 mapping sequence (Osteoarthritis Cartilage, 2014). In the present study, we focused on the meniscus change and osteophyte formation in early-stage knee osteoarthritis (OA). We examined whether there were any associations between the meniscus changes and the osteophyte formations, and also examined, if so, there were any site-specific differences for the associations in earlystage knee OA by using the magnetic resonance imaging (MRI)-based analyses.

Method: A total of 50 patients (mean age 59.7 years) who visited our out-patient clinic for knee pain between May and December 2012 were enrolled in this study. The severity of knee OA was classified by Kellgren-Lawrence (K/L) grading scale based on standing extendedknee X-ray images. All patients showed either K/L grade 0, 1 or 2, and were also performed 3TMRI for the affected knee. Diagnosis of knee OA for the subjects with K/L 0 was conducted using 3TMRI according to the method by Shama et al (ARD 2013). Patients who showed less than 174° of femoro-tibial tibial angle (FTA) were excluded from the study. Compartments of the knee joint was divided into 14 places of areas according to WORMS using sagittal and coronal two dimensional (2D) fat suppressed and T2 weighted image fast spin-echo sequence (TR=5,000 ms, TE=70 ms, FOV 160 mm, matrix=384×307, Slice thickness=3 mm, turbo-factor=17, Flip-angle=150, scan time=3:00). The severity of osteophyte and meniscus tear were semi-quantitatively evaluated according to the WORMS method. The medial meniscus extrusion distance (MMED) was also measured. Interrelationships between the osteophyte scores in medial femoral condyle (MFC) and medial tibia plateau (MTP) and the medial meniscus (MM) tear and MMED were examined.

Results: The patients showed the radiographic OA severities for K/L grade 0 (n=3), 1 (n=27) and 2 (n=20), respectively. Twenty-three of fifty patients were male, while remaining twenty-seven patients were female. No significant differences of FTA were observed between the patients with three different K/L grades. While the MMEDs were not associated with the osteophyte scores in MTP, the MMEDs were associated with the osteophyte scores in MFC (r=0.39, p<0.01). When the patients were divided into two groups in terms of the MMEDs by the cutline of 3 mm, the osteophyte scores in MFC in group 1 (MMEDs≥3 mm; 3.14) were significantly higher than those in group 2 (MMEDs<3 mm; 1.50)(p=0.03). On the other hand, the MM tear scores were associated with the osteophyte B212scores in MTP (r=0.32, p=0.03), while those were not associated with the osteophyte scores in MFC. In addition, when the patients were divided into two groups by the presence or absence of the MM tear, the osteophyte scores in MTP of the patients with MM tear (2.86) were significantly increased in comparison to those of the patients without MM tear (0.64, p=0.02).

Conclusion: The meniscus changes (MME and meniscus tear) were associated with the osteophyte formation in early-stage of medial knee OA. The associations were site-specific, that is; the MME were associated with the osteophyte in MFC, while the MM tears were associated with osteophyte in MTP.

Introduction: Muscle injury such as muscle strain frequently occurs in the hamstring, especially in the long head of the biceps femoris (BFl). Pre-exercise stretching has been widely performed as one of the methods for preventing the hamstring muscle strain in sports. It has been reported that less flexibility of the hamstring muscle-tendon unit assessed by passive range of motion (ROM) of the hip joint increases the risk of the hamstring muscle strain. In contrast, according to some recent literature, stretching appears to have no or little protective effect for sport injuries including the hamstring muscle strain. Taken together, no consensus has been reached as to whether stretching exercise can have positive effects for prevention of sports injuries. One of the possible reasons for the discrepancies is due to the joint at which the stretching exercise and flexibility test of the hamstring are performed. Since the hamstring which comprises the BFl, semitendinosus (ST), and semimembranosus (SM) is a biarticular muscle group, the muscles can be stretched by passive hip flexion or knee extension. Nevertheless, no study has examined the substantial effect of each of the two stretching maneuver on passive stiffness of the individual muscles, perhaps because it is impossible from a conventional evaluation of the torque-angle relationship to quantify the passive stiffness of a specific muscle. One of the methods to resolve the problem is to use ultrasound shear wave elastography which can quantify localized tissue stiffness along the principal axis of the probe. As a pilot study, we used this technique and compared passive stiffness of BFl, ST, and SM before and after an acute bout of static stretching by either hip flexion or knee extension.

Methods: In one healthy male subject, before and after 5 sets of 90-s stretching, passive lengthening measurements where the knee or hip joint was passively rotated to the maximal range of motion (ROM) were performed. During the passive lengthening, muscle stiffness (defined as shear modulus) of each muscle was measured by using ultrasound shear wave elastography.

Resuts: Both stretching maneuvers increased maximal ROM and decreased passive torque at a given hip joint angle. Passive muscle stiffness was prominently reduced in all of BFl, ST, and SM after passive knee extension stretching maneuver, whereas the stretching effect by passive hip flexion maneuver was pronounced in ST and SM, but not in BFl.

Conclusion: The present findings suggest that 1) the effects of hamstring stretching on individual passive muscles’stiffness vary between passive knee extension and hip flexion stretching maneuvers, and 2) stretching of the hamstring should be performed by passive knee extension rather than hip flexion which is commonly used as a warm-up exercise. Further research with large number of subjects is required to confirm our conclusion.

Background: During intermittent high-intensity exercise, the accumulation of hydrogen ions or the resulting fall in intramuscular pH has been considered a major factor contributing to muscle fatigue. Our recent study has shown that reversing the acidic muscle milieu by means of hyperventilation (HV)-induced respiratory alkalosis, implemented during the recovery period of repeated short pedaling sprints, is effective in attenuating the performance decrement associated with fatigue. The present study investigated whether HV-induced respiratory alkalosis could be applied to resistance training, expecting an increased number of repetitions able to be performed with HV.

Methods: Eleven power-trained athletes (1RM: 102.5-162.5 kg for bench press and 170.3-246.8 kg for leg press) performed 6 sets of bench press and 6 sets of leg press at 80% 1RM on the same day with and without HV during the last 30-s of 5-min inter-set recovery on 2 separate occasions (protocol A and B). HV was implemented before the 1st, 3rd and 5th sets for protocol A, and before the 2nd, 4th and 6th sets for protocol B (P_ETCO₂: 15-25 mmHg). Subjects breathed spontaneously for the entire 5-min during the alternate non-HV recovery periods. In each exercise set, lifting was continued until failure with the number of successful repetitions recorded. Wireless electro-goniometers were attached about the elbow and the knee joints to calculate the joint angular velocity per repetition. Blood [La^-] and pH were examined to report physiological strains of the exercises, and pH recovery resulting from HV.

Results: HV increased blood pH by 0.077±0.024 before the subsequent set (p<0.001). HV either increased (leg press, p<0.05) or maintained (bench press) the repetitions performed compared to the number achieved during the prior non-HV set. Whereas, the repetition number for the non-HV set was always fewer compared to the prior HV set (p<0.005). The sum of repetitions (protocol A+B) was greater for the HV than non-HV sets in both bench press (44±10 vs. 36±10 reps, p=0.001) and leg press (64±9 vs. 50±15 reps, p<0.001). Similarly, the joint angular velocity was enhanced by HV in both bench press and leg press, with the value being either maintained or greater (p<0.05) than the prior non-HV set. For the non-HV set, however, the joint angular velocity was almost always reduced (p<0.05) compared to the prior HV set. After the exercise, the blood [La^-] was greater (9.82±2.66 vs. 6.87±1.47 mM, p<0.001) and pH was lower (7.303±0.055 vs. 7.340±0.030, p<0.001) for leg press than bench press.

Conclusion: HV countered the reductions of repetitions and joint angular velocities associated with fatigue. These changes reflect a greater training volume and a greater training power output, which may be ultimately translated into a greater performance gain. The ergogenic effect was more pronounced for leg press, which incurred a greater physiological strain than bench press.

Objective: To investigate the cartilage metabolic status which can predict radiographic medial knee joint space narrowing (mJSN) in men in early forties without knee pain.

Design: In this prospective study, forty seven healthy male volunteers (41.6 y on average) who didn’t have knee pain and experience any traumatic episodes for the knee joints were enrolled.

Intervention: A radiograph of both knee were taken and the serum levels of pro-collagen type II C-propeptide (sPIICP) and collagen type II cleavage (C2C) and urinary level of cross-inked type II collagen C-telopeptide (uCTX-II) were measured at the time of study entry. Radiological progression of the knee OA is defined as mJSN greater than 0.3 mm in either of the knees during 3-years of follow up.

Results: The fourteen of 47 subjects were involved in the progression (P) group, while the remaining thirty-three subjects were involved in the non-progression (NP) group. No significant differences of the sPIICP, sC2C and uCTX-II in P group were observed in comparison to those in NP group at baseline. The sC2C/sPIICP of P group, but not uCTX-II/sPIICP, was significantly decreased in comparison to those of NP group (p<0.05). The age- and BMI- adjusted risk for the progression after 3-years of follow up in the lower tertile (T1) of the sC2C/sPIICP at baseline was significantly higher than that in the higher tertile (T3) [Odds ratio: 9.8 (95%CI: 1.4-67.4)].

Conclusion: In a three year prospective study, the lower sC2C/sPIICP was the risk factor for the radiographic mJSN in men in early forties without knee pain.

Objective: The aim of the present study was to investigate the involvement of AMPK in regulating skeletal muscle atrophy during hindlimb unloading.

Methods: Transgenic (AMPK-DN) mice expressing a dominant negative mutant of AMPKα1 in the skeletal muscle and their wild-type littermates (WT) mice were randomly divided into two groups: untreated preexperimental control (n=12/group) and unloading (n=12/group) groups. Mice of the unloading group were subjected to continuous hindlimb suspension for 2 weeks.

Results: Soleus muscle weight relative to body weight in WT mice was decreased by 30% in response to hindlimb suspension, whereas by 20% in AMPK-DN mice. The expressions of ubiquitinated proteins and MuRF1 mRNA, markers of ubiquitin-proteasome system activation, were upregulated by hindlimb suspension in WT mice, but no changes were observed in AMPK-DN mice. The expression of phosphorylated FoxO3a was decreased by hindlimb suspension in WT mice, but not in AMPK-DN mice. HSP72 expression was higher in AMPK-DN mice compared to WT mice during the experiment, and reduced more in WT mice by hindlimb suspension than AMPK-DN mice.

Conclusions: The present study demonstrated that the repression of skeletal muscle AMPK activation suppressed the progress of unloading-induced skeletal muscle atrophy. Our findings suggest that AMPK is involved in adaptation of skeletal muscle mass to atrophic stimuli.

Background: Cast immobilization can result in skeletal muscle atrophy. Excessive inflammatory response is now considered to be a crucial mechanism for muscle atrophy in cast immobilization. However, the mechanism of muscle atrophy via inflammation induced by immobilization remain incompletely understood. Toll-like receptors (TLR) 4, which are a family of innate cellular pathogen-recognition receptors, have been shown to play critical roles in activation of inflammation. A recent study proposed that TLR4 plays a pathogenic role in muscle atrophy, because TLR4-knockout mice showed both lower sepsis-induced muscle atrophy and ubiquitin ligases activation than wild-type mice. Interestingly, recent study was shown that short-term bed rest induced increased TLR4 expression in the skeletal muscle of healthy older adults. Therefore, increased of TLR4 expression may be an important factor for muscle atrophy and excessive inflammatory response associated with inactivity. We have examined the role of TLR4 in cast immobilization-induced skeletal muscle atrophy using TLR4-defective C3H/HeJ mice.

Methods: C3H/HeN mice and C3H/HeJ mice were divided into control and castimmobilization groups. Cast immobilization was imposed for 14 days. Muscle atrophy in the gastrocnemius muscle was evaluated by analyzing the muscle mass and cross-sectional area of the muscle fiber. Gene expressions in the gastrocnemius were evaluated by real time-Reverse Transcriptase -Polymerase Chain Reaction.

Results: Cast immobilization resulted in an increase in TLR4 mRNA expression in the gastrocnemius, and in a decrease in muscle mass of C3H/HeN mice. However, no difference in a decrease in gastrocnemius muscle mass, or in the gastrocnemius fiber cross-sectional area at day 14, in the cast immobilized group. Cast immobilization-induced increase in ubiquitin ligase mRNA was not affected by defective TLR4. In control groups, TNF-α mRNA expression in C3H/HeJ mice was lower than that in C3H/HeN mice. However, this variable did not differ between the cast-immobilized groups of the two mouse models at day 14.

Conclusion: Our findings in C3H/HeJ mice suggest that TLR4 may not play an essential role in immobilization-induced muscle atrophy.

Sarcopenia is the age-related loss of skeletal muscle mass and strength leading to physical frailty, loss of independent daily living, increased lifestyle-related disease, and high health care costs. One concern is that the incidence of sarcopenia is increasing in the world. There is a great deal of interest in strategies to prevent or reverse sarcopenia in our aging population.

Aging muscle consists of fewer myofibers compared to adult muscle and these myofibers show signs of atrophy and increased muscle adiposity. Adiposity in skeletal muscle has been widely recognized as one of the hallmarks of sarcopenia. Adult skeletal muscle has a remarkable regenerative capacity, largely mediated by myogenic stem cells, termed satellite cells (SCs). SCs are located in the plasma membrane of myofibers beneath the basement membrane and are mitotically quiescent in adult muscle. During muscle regeneration, satellite cells are activated, giving rise to myoblasts that proliferate, differentiate and fuse together or fuse to pre-existing muscle fibers to produce fully mature muscle fibers. However, skeletal muscle regeneration is markedly impaired with age. Recently we demonstrated that the number of activated, proliferated, and differentiated SCs was lower in old rats compared with young rats after muscle damage. In addition, old rats exhibited impaired muscle regeneration and increased intermuscular adipocytes post-injury. Our data suggest that impaired regeneration of old skeletal muscle might be attributed to changes in several functions of SCs. We indicated that rat SCs are multipotent cells that can undergo not only myogenic, but also adipogenic differentiation in vitro and in vivo, and their adipogenic responses increase as a function of age.

Inflammation is an obligatory event in skeletal muscle injury. Recovery of skeletal muscle injuries requires severely injured myofibers to be degraded, phagocytized, and replaced via the migration and maturation of SCs. It is well established that macrophages are the dominant inflammatory cell type during early muscle injury and may contribute to skeletal muscle regeneration by facilitating myofiber repair via the production of inflammatory cytokines, chemokines, and growth factors. Recently we demonstrated that the number of activated macrophages within skeletal muscle was lower in old rats compared with young rats after muscle damage. In addition, our DNA chip data has indicated that the expression of genes including inflammatory cytokines, chemokines, and growth factors was attenuated during the regeneration of aged skeletal muscle. These data suggest that the impaired inflammatory response to muscle damage that occurs with aging may contribute to the impaired muscle regenerative capacity and to increased muscle adiposity, both characteristic of aged muscle. These factors may be underlying causes of sarcopenia.

Objective: To investigate the effects of treadmill running exercise on bone density and bone strength in young mice.

Methods: Four-week-old male C57BL/6 mice (n=10) were assigned to either the control sedentary group (CON, n=5) or the treadmill running exercise group (TRE, n=5). Mice in the TRE group were forced to run on a treadmill at a rate of 6-18 m/min, 30 min/day, 5 days/week for 16 weeks. The mice in both groups were euthanized at 20 weeks of age. The right and left lower limbs, skeletal muscle, and white adipose tissue were removed for analysis. Bone density (mg/cm ³) was measured in the right limb using microcomputed tomography, and maximal breaking force (N) was determined in the left femur using a three-point bending test as an indicator of bone strength.

Results: The TRE and CON groups did not significantly differ with respect to daily food intake during the study period or body weight at 20 weeks of age. Differences in white adipose tissue and skeletal muscle weight of 20-week-old mice in the TRE and CON groups were also not significant. Cortical bone density was significantly higher in the TRE group than in the CON group (p<0.05). However, there were no significant differences in cancellous bone density, total bone density or maximum breaking force between the TRE and CON groups.

Conclusions: Treadmill running exercise for 16 weeks can increase cortical bone density of tibia in young mice, but does not improve bone strength in femur.

ntroduction: Type 1 diabetes impairs Ca ²⁺ handling in many tissues such as cardiac muscle, platelets, kidney and liver. In skeletal muscle, the diabetic state increases resting intracellular Ca ²⁺ ([Ca ²⁺] _i) levels and induces activity of Ca ²⁺-dependent proteolytic pathways. In skeletal muscle, dysfunctional contractile activity has been linked to impaired [Ca ²⁺] _i regulation. Muscle force production is impaired and fatigability and muscle fragility deteriorate with diabetes. Recently, we succeeded in measuring in vivo [Ca ²⁺] _i within the mixed fiber-type rat spinotrapezius muscle ¹⁾ following contractions. In this preparation, intramyocyte injection of a high [Ca ²⁺] bolus revealed a depressed Ca ²⁺ buffering capability in diabetes which corresponded with the elevated post-contraction [Ca ²⁺] _i ²⁾. Unfortunately, that preparation did not permit resolution of between fiber type effects on the profile of [Ca ²⁺] _i following contraction in Type 1 diabetes which remain to be resolved. We tested the hypotheses that: 1. The rise in resting [Ca ²⁺] _i evident in diabetic rat slow-twitch muscle would be exacerbated in fast-twitch muscle following contraction. 2. These elevated [Ca ²⁺] _i levels would relate to derangement of microvascular O₂ pressures (PmvO₂) rather than sarcoplasmic reticulum (SR) dysfunction per se.

Methods: Adult male Wistar rats were divided randomly into diabetic (DIA: Streptozotocin i.p.) and healthy (CONT) groups. Four weeks later extensor digitorum longus (EDL, predominately type II fibers) and soleus (SOL, predominately type I fibers) muscle contractions were elicited by continuous electrical stimulation (120 s, 100 Hz). Ca ²⁺ imaging was achieved using Fura-2 AM in vivo. Phosphorescence quenching techniques were used to measure PmvO₂.

Results: DIA increased fatigability in EDL (p<0.05) but not SOL. In recovery, SOL [Ca ²⁺] _i either returned to its resting baseline within 150 s (CONT, 1.00±0.02 at 600 s) or was not elevated in recovery at all (DIA, 1.03±0.02 at 600 s, p>0.05). In recovery, EDL CONT [Ca ²⁺] _i also decreased to values not different from baseline (1.06±0.01, p>0.05) at 600 s. In marked contrast, EDL DIA [Ca ²⁺] _i remained elevated for the entire recovery period (i.e., 1.23±0.03 at 600 s, p<0.05). The inability of [Ca ²⁺] _i 40 to return to baseline in EDL DIA was not associated with any reduction of SERCA1 or SERCA2 protein levels (both increased 30-40%, p<0.05). However, PmvO₂ recovery kinetics were markedly slowed in EDL such that mean PmvO₂ was substantially depressed (CONT, 27.9±2.0 vs DIA, 18.4±2.0 mmHg, p<0.05) and this behavior was associated with the elevated [Ca ²⁺] _i. In contrast, this was not the case for SOL (p>0.05) in that neither [Ca ²⁺] _i nor PmvO₂ were deranged in recovery with DIA.

Conclusion: In conclusion, compromised Ca ²⁺ buffering and elevated [Ca ²⁺] _i following an in vivo fatiguing tetanic contraction occur preferentially in the fast twitch EDL rather than the slow twitch SOL muscle. (The rest of omitted)

Autophagy is a large-scale degradative system, by which cellular constituents, including cell organelles and cytosolic proteins, are broken down via the lysosomes. Autophagy initiates with the formation of smooth limiting membrane, which extends and sequesters surrounding cytoplasm to form a double-membraned autophagosome. Autophagosome then fuses with the lysosome to mature into autolysosome. It was thought previously that sequestered cytoplasmic components in the lumen were degraded completely by lysosomal hydrolases to their elements, such as amino acids, fatty acids, sugars, etc. However, it has been shown recently that some degradation intermediates or products are discharged to the extracellular milieu. As these compounds derive from the relevant tissues or cells, characterization of these excreted compounds may be beneficial to understand cell type- or tissue type-specific autophagic process.

Using mass spectrometry, we extensively analyzed peptides and low-molecular compounds released from HeLa cells and mouse embryonic fibroblasts (MEF) when they were incubated with Krebs bicarbonate buffer (KRB)(nutrient deprivation conditions). We found that in addition to amino acids significantly more peptides were released from the control cells than those from the cells treated with E64d plus pepstatin A (lysosomal proteinase inhibitors). Identification of these discharged peptides will be reported.

Introduction: Athletic season is roughly divided into three seasons in Japan, namely the physical training season in winter, the pre-competition season in spring and the competition season between summer and autumn. Therefore, it is generally thought that aims, contents, volume, and programs of workout are different by seasons. For that reason, physical fitness levels of athletes may fluctuate through a year. Thus, the purpose of this study was to identify seasonal changes in physical fitness of adolescent track and field athletes.

Methods: Subjects were 11 boys and 7 girls of two different high schools. Tests are performed in each season. We applied assessments of physical fitness: 100 m sprint running, three kinds of vertical jump (squat jump, counter movement jump, and drop jump), single-joint isometric torque (knee extension, knee flexion, dorsiflexion, and plantar flexion), and anthropometric characteristics.

Results: Friedman test and post hoc Wilcoxon test revealed that many of physical fitness parameters of boy athletes were higher at the competition season compared with in the other seasons. In girls, only counter movement jump and body weight were significant differences among seasons.

Discussion: This study was found that physical fitness of adolescent track and field athlete varied through seasons. Especially, it was trend to improvement of the muscle strength and power output in the competition season.

Conclusion: Seasonal changes were found in physical fitness of adolescent track and field athletes. Moreover, sex differences were found in the trends in seasonal changes.

To investigate the sprinting ability with change of direction (COD) involving decision making in female soccer players to compare it with athletes in a different sports (soccer vs. track-and-field), as well as to compare among competitive levels (Higher performance group [HPG] vs. Lower performance group [LPG]).

Thirty-three university female athletes participated in this study and were divided into 4 groups (n=24: soccer [n=11: HPG, n=11: LPG] n=9: track-and-field). The following protocols were utilized to determine the sprinting ability in a straight line and with COD involved in the decision making. We measured the time from the 20 meter (m) sprint test for the straight sprinting ability. We also conducted the 20 m sprint with cutting movement 90 degree at the 10 m point where athletes needed to make a decision whether they turn right or left according to the light stimulation at 2.5, 5 and 7.5 m using infrared timing gates (Smart-Speed).

The 20 m straight sprint time among track-and-field athletes were significant faster than soccer players (p<0.05). There were no significant differences between soccer players and track-and-field athletes on other measured variables. In the female soccer groups, the 20 m sprint time among did not differ significantly between HPG and LPG. However, all sprint times of COD involving the decision making with HPG were significantly faster than LPG (p<0.05).

Our study suggested that the COD ability with decision making was not correlated to the 20 m sprinting performance in a straight line.

The purpose of the present study was to get the reference value of agility of visually impaired soccer players in accordance with the blind class. Twenty one male visually impaired soccer players (B1: n=12, B2: n=4, B3: n=5) and twelve male university soccer players participated in this study voluntarily. Subjects’ height, body weight, body mass index, body fat percentage. The agility performance at side step test was evaluated by using two support rope. The kind of the support rope was 3 fulcrums support rope (the weight mobility type=WMT) and 1 fulcrum support rope in (the pendulum mobility type=PMT). The results of there were no difference on the blind class by used WMT method in the side-step test. But there was a difference on the blind class by used PMT method in the side-step test (p>0.05). Sighted subjects were higher recorded by used PMT method in blindfold (p>0.05). In conclusion, the findings of the present study indicated the reference value of agility ability of each of the blind class. Suggested that they had been relationship in ability to recognize the space involved with pendulum mobility operation. Low vision was suggested that the superior agility performance with spatial perception than blind.

Introduction: Characteristics of muscular morphology is assumed to be one of the determining factors for its mechanical function and a particularly important evaluation index in the field of sports. Muscle evaluation is generally performed using ultrasound and MRI with major endpoints of thickness and cross sectional area. However, due to its complicated anatomy, a skeletal muscle presents different area depending on its cross section site. Therefore, muscle volume should be used as an index to evaluate the whole muscle. The narrow observable field of view in ultrasound and the long imaging time of an MRI make these methods unsuitable for the evaluation of muscle volume. In contrast, CT allows for short measurement time and clear image over a wide area. It can also selectively extract data from each cross sectional data to build a three-dimensional image (3D-CT) of the target muscle with accurate measurement of the muscle volume. This study was aimed to examine the efficiency and usefulness of the whole muscle extraction by 3D-CT and the measurement of muscle volume.

Methods: Cross sectional images of the thigh at slice thickness 1 mm using multi-slice CT were obtained from male athletes specializing in track and field. Quadriceps femoris (QF) and hamstrings (Ham) were selected as target muscles and selectively extracted 10 times using an image analysis work station made by AZE company. We evaluated the whole form, origin, termination and muscle volume of each muscle. As quantitative detail, we calculated the mean, standard deviation, and coefficient of variation (CV) of the volume.

Results and Discussion: The mean muscle volume were 2341.3±14.78 cm³ for QF and 1128.3±18.04 cm³ for Ham. CV of QF and Ham were less than 1% and less than 2%, respectively. CT is known to be superior in spatial resolution. Both quadriceps femoris and hamstrings have multiple origins and terminations, all of which were clearly observed in this study. Accurate muscular morphological evaluation is extremely important in elucidating characteristics of the muscular force exertion. This study suggested that 3D-CT is a useful method for evaluating the anatomical basis of the human body in detail. We will further clarify its utility by comparing other muscle volume calculation methods in the future.

Age-related motor organ failure is the major problem in super-aged society because it is leading to care requirements or bedridden. Although locomotive syndrome is recently defined as the individual state with gait disturbance having functional decline of motor organs; bone, cartilage, intervertebral disc, nerve and skeletal muscle, it has been practically difficult to treat it because the cause is complicatedly multifactorial, such as osteoporosis, osteoarthritis, sarcopenia and so on. Superoxide dismutase 2 (SOD2) is the endogenous mitochondrial antioxidant enzyme which converts superoxide anion to hydrogen peroxide to maintain the reduction-oxidation balance in cells. The physiological role of SOD2 and the pathological role of superoxide in degeneration of motor organs have been investigated in our previous study using tissue-specific SOD2-deficient mice. Here we focused on the effect of mitochondrial superoxide and SOD2 imbalance in the development of the locomotive syndrome.

We generated conditional SOD2-deficient mice crossbreeding Sod2 flox mice with dentin matrix acidic phosphoprotein (DMP1) promotor Cre, type2 collagen (Col2) promotor Cre and human skeletal actin (HSA) promotor Cre mice to find tissue-specific phenotypes in osteocyte, chondrocyte and skeletal muscle, respectively. Osteocyte-specific SOD2 deficiency showed both increased expression of sclerostin leading to suppressed bone formation and increased expression of receptor activator of NF-κB ligand (RANKL) causing activated bone resorption. As a result, the mutant mice in vivo showed remarkable bone loss in an age-dependent manner, composing increase of disorganized osteocytic canalicular networks and decrease of live osteocytes number. Chondrocyte-specific deletion of SOD2 promoted mitochondrial superoxide overproduction, mitochondrial dysfunction and impaired extracellular matrix homeostasis, leading to spontaneously accelerated cartilage degeneration both during aging and under mechanical loading. Furthermore skeletal muscle-specific SOD2-deficient mice displayed increased selective loss of enzymatic activity in mitochondrial respiratory chain complexes and reduced ATP content in their muscle, leading to severe disturbances in exercise activity.

These findings demonstrate that mitochondrial superoxide in common plays a pivotal role in the development and progression of osteoporosis, osteoarthritis and muscle weakness, so to speak, age-related locomotive dysfunction, and suggest that the regulation of superoxide balance in the local tissue or in the entire body is a promising target for the treatment of locomotive syndrome.

Objective: To investigate the effect of combined increased walking and stair-climbing, and walking with blood flow restriction (BFR) in working muscles on leg muscle thickness in older adults.

Methods: Nineteen older subjects were divided into the following three groups: normal walking and stair-climbing (WS), WS and BFR-walk once a wk (WS-BFR1), and WS and BFR-walk twice a wk (WS-BFR2). All subjects were instructed to walk at a self-selected, faster pace than usual for ≥30 min per session, ≥2-4 days per wk, and climb ≥5 flights of stairs per day, ≥4 days per wk for 11 wk. Additionally, the WS-BFR1 and WS-BFR2 groups performed 20 min of a BFR-walk at a pre-determined exercise intensity of 70-85% of the age-predicted maximum heart rate.

Results: Two-way repeated measures analysis of variance showed that the time effects were significant (p<0.01) for muscle thicknesses (MT) of the posterior aspects of the thigh (PT, WS: 8.9%, WS-BFR1: 11.7%, WS-BFR2: 11.8%) and lower leg (PL, WS: 3.0%, WS-BFR1: 1.1%, WS-BFR2: 6.6%). However, there was no significant difference in these values of MT among all the groups. For the 10-m walking time, the main effect of time was significant (p<0.05), but the interaction was not significant.

Conclusions: Walking and stair-climbing training can increase MT of the PT and PL, and improve walking performance in older adults, whereas a BFR-walk once or twice a wk may not produce additional training effects.

Objective: The purpose of this study was to examine the effect of long-term training program combining increased physical activity and walking with blood flow restriction (BFR) on locomotive syndrome in elderly adults.

Methods: A total of 13 relatively active subjects (11 men and 2 women) aged 67.2±4.0 years were assigned to the increasing physical activity (walking and climbing stairs) group (CON-W, n=6) or blood flow restriction walk training group (BFR-W, n=7). Both groups performed more than 30-min walking training at a pace faster than usual for at least 3 days and climbed more than 5 flights of stairs per day for at least 4 days per week for 6 months. Additionally, BFR-W group performed a treadmill walking for 20 min once a week at an exercise intensity of 70-85 % of age-predicted maximal heart rate (HRmax=220 - age). Locomotive syndrome risk tests (stand-up test, two-step test, 25-question risk assessment) were performed.

Results: There was no main effect of group, time, and interactions between group×time in the two-step test, stand-up test, and 25-question risk assessment.

Conclusion: Long-term walking and stair-climbing training programs did not improve the outcomes of locomotive syndrome risk test in physically active elderly subjects.

Objective: This study aimed to investigate the relationship between physical activity (PA) and locomotive syndrome after a 3-month exercise intervention of walking and stair climbing in elderly Japanese individuals.

Design: Eighteen elderly participants (mean age 68±5 years) were equally assigned to a normal walking and stair climbing (WS) group or a WS and walking with blood flow restriction (WS+BFR) once a week group. Both the groups were instructed to walk at a faster pace than usual for more than 30 min per day and climb more than 5 flights of stairs per day, for more than 4 days per week in the WS group and for more than 3 days per week in the WS+BFR group for 3 months.

Methods: PA was measured using a wristband type acceleration sensor. Locomotive syndrome risk tests (the two-step test, the stand-up test, and 25-question risk assessment) were performed before and after the intervention.

Results: No significant difference was found between the groups considering the PA. Step counts over 3 metabolic equivalents (METs) per day increased by exercise intervention (p=0.014). Increase in vigorous PA (≥6 METs) was positively correlated with the stand-up test score (r=0.490, p<0.05), but not the two-step test score and 25-question risk assessment.

Conclusions: These results suggest that increase in vigorous PA via walking and stair climbing might lead to improving locomotive syndrome risk in elderly Japanese individuals, regardless of walking with blood flow restriction once a week.

Objective: To evaluate relationships among locomotive syndrome (LS), daily physical activity (PA), physical function, and body composition measurements in elderly Japanese individuals.

Materials and Methods: This study included 39 elderly participants (mean age, 68.4±5.5 years). All participants completed three LS risk assessments, the two-step test, stand-up test, and 25-question geriatric locomotive function scale (GLFS). To assess LS, a stage 1 LS (LS-1) cutoff was applied. Physical function was assessed using the chair stand, sit-up, 10-meter (m) walking time, and 10-m zigzag walking time (ZWT) tests. Additionally, the isometric strength of the knee extensors and flexors were evaluated and body composition measurements were performed. Habitual daily PA (step count and intensity of PA) was evaluated using a three-axis, high-frequency wrist accelerometer.

Results: The proportion of LS-1 in this study population was 35.9% (14/39). The number of daily steps, 10-m walking time, 10-m ZWT, knee extension strength, and knee flexion strength were significantly higher among non-LS participants than among LS-1 participants. The 10-m walking time, 10-m ZWT, knee extension strength, and knee flexion strength were significantly higher and the chair stand score tended to be higher among non-LS participants than among LS-1 participants. For all participants, the stand-up test scores correlated with the 10-m walking times, 10-m ZWTs, chair stand scores, sit-up scores, and knee extension strength.

Conclusions: LS might be associated with daily PA, physical function, and isometric knee extension strength. Furthermore, the stand-up test is a good index for LS screening in elderly individuals.

Objective: This study aimed to evaluate the effects of a long-term training program combining increased physical activity and walking with blood flow restriction (BFR) on the body composition and glycated hemoglobin (HbA1c) levels in elderly subjects.

Methods: A total of 13 subjects (age, 67±1 years) were assigned to the walking and stair-climbing (WS) group (6 men) or the WS and BFR-walk (BFR) group (5 men and 2 women). Both groups were instructed to complete walking sessions of more than 30 min, at a self-selected, faster pace than usual, and to climb more than 5 flights of stairs per day, for at least four days per week. In addition, the BFR group completed a 20-min treadmill walking session on a weekly basis, for 6 months, at a pre-determined exercise intensity of 70-85% of the age-predicted maximum heart rate and with BFR of 100-120 mmHg applied to both thighs. The measured outcome variables included height, body weight (BW), waist circumference (WC), body mass index (BMI), muscle mass, fat mass, body fat (%Fat), and HbA1c levels, measured at baseline, at the 3-month midpoint of the program, and at the 6-month endpoint.

Results: After the 6-month intervention, the BW, WC, BMI, fat mass, %fat, and HbA1c levels were decreased compared to baseline in both the WS and BFR groups (p<0.01), with the muscle mass increasing in both groups (p<0.05).

Conclusions: A 6-month walking and stair-climbing exercise program was effective in improving body composition and HbA1c levels in elderly subjects, with no added benefits of BFR.

Background: In 2007, the Japanese Orthopedic Association (JOA) proposed the term locomotive syndrome (LS) to designate a condition in high-risk groups of patients with musculoskeletal diseases who are highly likely to require nursing care. LS is caused by weakening of the musculoskeletal organs, such as the bones, joints and muscles. Disorders of these organs leads to self-transportation disabilities. These conditions force people suffering from this syndrome to require outside care and support. Therefore, to prevent the decline into disability, patients need to maintain their health, especially their locomotor function. To prevent locomotor dysfunction, the JOA has carried out numerous campaigns to increase the awareness of LS. However, there are no accurate studies regarding the recognition of LS. Therefore, we have started to survey the recognition of LS since 2013 to elucidate the effects and trends of the recognition of LS and the promotion campaigns using orthopedic outpatient cohost.

Methods: To investigate the recognition of LS, we conducted a questionnaire survey including both the 25-question Geriatric Locomotive Function Scale (GLFS-25) and/or the “loco-check” in approximate 1,000 orthopedic outpatients at Juntendo University Hospital (Tokyo, Japan) from March to June (for 3 months) since 2013 (for 3 years).

Results: We have performed these surveys for 3 years (in 2013, 2014 and 2015). In first year, we surveyed the recognition of LS and found 24.6% of outpatients knew about LS in 2013. In 2014, a total of 26.4% of the patients knew about the concept of LS, which was increased 1.8% in comparison to our survey in 2013. With regard to the prevalence of LS in orthopedic outpatients, 60.5% (734 of 1,027 people who answered the questions) were classified into the LS high-risk group as determined using the GLFS-25. The prevalence of LS was 54.9% in males and 64.3% in females. We also resurveyed the recognition of LS and the prevalence of LS in 2015, and we are analyzing these acquired data in 2015 as on-going study.

Conclusion: We investigated the recognition of LS and the prevalence of LS using an outpatient cohort from the Tokyo area. This study demonstrated that the recognition of LS is a little bit increasing. Our outpatient-based survey is therefore considered to positively help obtain a better understanding of the effects and trends of promoting the concept of LS.

Objective: The purpose of this study was to investigate whether blood flow restriction (BFR) walking results in an acute increase in muscle size and decrease in maximal strength as well as metabolic accumulation in older adults.

Methods: Ten older men and 8 older women (mean±standard error; age, 68±1 years; height, 161.8±1.8 cm; weight, 60.7±8.5 kg) walked for 20 minutes with BFR at a pre-determined speed (3-4 km/h). Muscle thickness (MT) was measured at the following four sites: knee extensors (KE) and flexors (KF) at 50% of the thigh length and dorsi flexors (DF) and plantar flexors (PF) at 30% of the lower leg length. The maximal voluntary isometric strength of KE and blood lactate concentrations were measured. All parameters were measured before and immediately after the exercise session.

Results: MT increased at all sites after BFR walking (KE: pre 28.9±1.0 mm, post 32.3±0.9 mm; KF: pre 53.3±1.2 mm, post 55.2±1.4 mm; DF: pre 23.9±0.6 mm, post 24.7±0.5 mm; PF: pre 61.0±1.1 mm, post 63.8±1.0 mm). The maximal voluntary isometric strength of KE decreased after BFR walking (pre, 144±9.5 Nm; post, 136.5±8.7 Nm). Blood lactate concentration was significantly elevated after BFR walking (pre, 1.3±0.1 mol/l; post, 1.9±0.2 mol/l).

Conclusion: BFR walking causes an acute increase in muscle size and decrease in maximal strength as well as metabolic accumulation in older adults.